[big block fiero]

I would really like to hear L/S ratio comparisons made in conjunction with different valve seat angles, rocker ratio's, and low lift flow changes that also make an engine exibit symptoms similar to these L/S ratio changes.

Where I am going with this is that these changes all alter the pressure recovery dynamics of the mixture flow across the valve seats. Putting it another way, if the mixture velocity is greater and more consistent at low lift even when the piston may not be moving enough air near tdc, then, the fuel will stay better vaporized. Try to realize that when the intake valve/port shuts and is then waiting for the next intake cycle, the velocity has also stopped. So then what do you think happens to the fuel that was suspended in the air stream and where does its enertia make it stop, on the next opening cycle just as the valve opens, the seat kind of drools a little liquid fuel at first.

Say you have long rods but also have 60 degree valve seats. Less air would be moving near tdc due to long rods and reduced piston speed, but the 60 degree seats will create more low lift flow velocity because they move less air thru a smaller opening at low lift -------- conversely to this now say youve got a short rod engine that picks up mixture velocity sooner after the overlap induced velocity has deminished. Now this motor could run 30 degree seats, higher ratio rockers, ect, with potentially less mixture related problems because the pressure recovery dynamics aren't as bad with the shorter rods.

Now---- to expand on this, what if you,ve got a super vizard carborator that vaporizes fuel better? Are you then as concern about good pressure recovery dynamics that vaporizes fuel better during low lift flow? What if you are running propane or a diesel? What L/S ratio would be desired then?

Next issue----is a particular L/S ratio or power stroke piston movement better suited to the combustion characteristics of a quenchless combustion chamber or a less quench area dished or nascar style dished piston?

Matt kneen, mpls mn.